Aeration drain plug for dishwashers

ABSTRACT

There is disclosed a dishwasher having a drain plug in the conduit leading from the sump to the pump inlet. The drain plug may be removed and replaced by an aeration drain plug which is connected to a valved air line for selectively injecting air into the pump inlet to decrease pump efficiency and thereby decrease pump discharge pressure to provide a soft wash feature for fine china, crystal and the like.

United States Patent 1191 Guth 1 1 AERATION DRAIN PLUG FOR [58] Field of Search 134/56 D, 57 D', 58 D, 95, 134/102,103,148,155,186

[56] References Cited UNITED STATES PATENTS 3,134,386 5/1964 Jenkins 134/102 1 June 17, 1975 3,384,098 5/1968 Swetnam 134/58 D 3,621,856 11/1971 Guth 134/58 D FOREIGN PATENTS OR APPLICATIONS 128,969 11/1945 Australia 134/56 D Primary Examiner-Robert L. Bleutge ABSTRACT There is disclosed a dishwasher having a drain plug in the conduit leading from the sump to the pump inlet. The drain plug may be removed and replaced by an aeration drain plug which is connected to a valved air line for selectively injecting air into the pump inlet to decrease pump efficiency and thereby decrease pump discharge pressure to provide a soft wash feature for fine china, crystal and the like.

9 Claims, 6 Drawing Figures PATENTEDJUN 17 I975 3. 889,697

SHEET 1 FIG. 5

FIG. 6

l (PRIOR ART) FIG.

AERATION DRAIN PLUG FOR DISHWASHERS BACKGROUND OF THE INVENTION For some time, the assignee of this invention has been offering a soft wash feature in dishwashers. The soft wash feature is intended for fine china, crystal and other fragile tableware to allow machine washing thereof while minimizing the possibility of damage. This is accomplished by injecting air into the pump inlet which reduces pump efficiency thereby decreasing pump outlet pressure. As discussed more fully hereinafter, the provision of a soft wash feature has required a specially designed conduit between the sump and the pump inlet. Accordingly, it has been necessary to manufacture, inventory and use two rubber pump inlet conduits. It would be desirable to provide dishwashers with or without an aeration capability which utilize the same pump inlet conduit.

It is accordingly an object of this invention to provide dishwashers with and without aeration capabilities utilizing an interchangeable pump inlet conduit.

In summary, this invention comprises a dishwasher including a tub and a movable door providing together a wash chamber; a rack and means mounting the rack for movement into and at least partially out of the wash chamber; and means for spraying washing liquid toward the rack including a spray mechanism in the wash chamber, a pump having an outlet in communication with the spray mechanism and an inlet, a conduit providing communication between the wash chamber and the pump inlet and including a closed side wall having a single opening therethrough for alternatively receiving an imperforate plug or an aeration plug, an aeration plug in the opening including an air passage therethrough, and means for delivering air to the passage.

IN THE DRAWINGS FIG. I is a front elevational view of a prior art dishwasher, certain parts being broken away for clarity of illustration;

FIG. 2 is a view similar to FIG. 1 illustrating the principles of this invention;

FIG. 3 is an exploded isometric view of the pump inlet conduit and the two alternately usable plugs therefor;

FIG, 4 is a cross sectional view of the pump conduit and aeration plug as viewed along line 4-4 of FIG. 3 as viewed in the direction indicated by the arrows;

FIG. 5 is a cross sectional view illustrating sealing of an imperforate plug to the pump inlet conduit; and

FIG. 6 is a top schematic view illustrating the flow lines around the aeration plug.

Referring to FIGS. 1 and 2, there are illustrated a pair of automatic dishwashing machines 10 of basically the same type including a cabinet 12 and a door 14 providing therebetween a wash chamber 16. The door 14 is hinged along its lower edge and may be pivotally moved between the illustrated closed vertical position and a generally horizontal open position providing access to the wash chamber 16 through an opening 18. Upper and lower article receiving racks 20, 22 are mounted for linear movement into and at least partially out of the wash chamber 16 by roller-guide arrangements 24, 26 to facilitate loading and unloading of tableware therein.

The lower portion of the wash chamber 16 is defined by a sloping floor or tub bottom 28 separating the wash chamber 16 from a pump-motor compartment 30. In the compartment 30 is a pump 32 driven by a suitable electric motor 34. The pump 32 acts to recirculate washing liquid during operation of the dishwasher l0 and to drain washing liquid out of the dishwasher 10 at the completion of a rinse or washing cycle in response to control from a timer 36.

To these ends, the pump 32 includes an inlet 38 and an outlet 40 rigid with a conduit 42. The conduit 42 extends upwardly through a hump 44 in the tub bottom 28 in sealed relation therewith to an elevation above a generally horseshoe shaped resistive heating element 46 which acts under control of the timer 36 to heat the wash chamber 16 during the drying cycle. The conduit 42 is in fluid communication with a spray mechanism 48 comprising a hollow spray arm 50 mounted for rotation about a central axis for spraying washing liquid toward the racks 20, 22. Comprising an integral part of the tub bottom 28 or secured about an opening therein is a sump 52 having a downwardly extending outlet conduit 54.

In FIG. 1, a rubber boot or pump inlet conduit 56 connects the outlet conduit 54 of the sump 52 to the inlet 38 of the pump 32 for loading the pump and allowing circulation of washing liquid. The pump inlet conduit 56 is of generally L-shape or elbow configuration comprising a closed side wall 58 having a downwardly extending fitting 60 providing a passage therethrough closed by an imperforate plug 62. The side wall 58 also provides a laterally extending aeration fitting 64 providing an opening therethrough in communication with an air hose or conduit 66. A solenoid operated valve 68 is positioned in the condiut 66 and controlled by the timer 36 for selectively allowing air passage through the hose 66. The interior of the pump inlet conduit 56 is designed to create an area of low pressure, such as a vortex, adjacent the fitting 64 to suck air through the hose 66 when the valve 68 is opened.

Referring to FIG. 3, the imperforate plug 62 is illustrated as comprising a tubular body 70 having an enlarged end cap 72 at one end thereof and a peripheral flange 74 intermediate the body 70. There is accordingly provided a receptacle or chamber 76 inside the plug 62 for purposes more fully explained hereinafter. The plug 62 is conveniently inserted into the fitting 60 with a clamp positioned about the fitting 60 to reside between the end cap 72 and flange 74. The end cap 72 is of sufficient size to prevent overinsertion of the plug 62 into the fitting 60.

The dishwasher l0 accordingly provides a normal wash cycle when the valve 68 is closed and a soft or aerated wash cycle when the valve 68 is open.

The fitting 60 and plug 62 provide two functions. After assembly but before shipment of the dishwasher 10, it is common to run through one operating cycle to assure that all components are functioning. Accordingly, water is introduced into the wash chamber 16 and circulated by the pump 32. At the end of the last wash or rinse cycle, the pump 32 is controlled by the timer 36 to discharge water from the dishwasher 10. Since most pumps are inherently incapable of discharging all of the water from the dishwasher, a water residue typically in the range of a few pints remains in the conduit 56. It is highly desirable to drain this residue from the conduit 56 since dishwashers are typically shipped in cardboard containers which would be water damaged if the container were turned upside down. To

drain the conduit 56, the wire clamp securing the plug 62 in the fitting 60 is removed followed by removal of the plug 62. After the residual water drains out of the conduit 56, the plug 62 is reinserted into the fitting 60 and the clamp therefore replaced.

During operation of dishwashers, items such as marbles, bobby pins, pebbles and the like occasionally get in the wash chamber 16 and pass into the sump 52 and conduit 56. The receptacle 76 provided by the plug 62 acts as a trap for such items. Accordingly, when a serviceman is called upon to perform any repair of dishwashers, one of the things habitually done is to with draw the plug 62 and remove any such particles from the receptacle 76. The fitting 60 is conveniently downwardly extending from the conduit 56 to provide the capability of draining the conduit 56 and to provide a trap for small items which may damage the pump 32, create noise or the like. It will be apparent that the plug 62 is also operative to drain the conduit 56 when it is desirable, during a service call, to perform maintenance or repair on the pump 32.

Referring to FIGS. 2-4, there is provided a rubber boot or pump inlet conduit 78 which is illustrated as being of substantially the same configuration as production model conduits for dishwashers which do not have an aerated wash capability. The conduit 78 is illustrated as of generally L-shaped configuration having a closed side wall 80 defining an inlet 82 and an outlet 84. The conduit 78 includes a fitting 86 providing a single opening 88 through the side wall 80 for alternately receiving the imperforate plug 62 or an aeration plug 90.

The conduit 78 is desirably made of a relatively flexible rubber material providing stiffening flanges 92, 94 about the inlet 82 and outlet 84 respectively. A plurality of external ribs 96 may be provided as desired. As illustrated in FIG. 4, a vane 98 projects inwardly from the outer radius of the elbow to promote laminar, as opposed to turbulent, flow in the conduit 78. A noise suppressing baffle 100 may be provided adjacent the inner radius of the elbow as desired.

The assignee of this invention presently assembles dishwashers which do not have an aerated wash capability by installing the conduit 78 as illustrated in FIG. 2, placing the plug 62 in the fitting 86 and placing a clamp 102 about the fitting 80 as illustrated in FIG. 5.

In order to provide a dishwasher having both nonaerated and aerated wash features, the fitting 90 is utilized. The fitting 90 includes a tubular body 104 having an enlarged cap 106 on one end thereof providing a receptacle or compartment 108. Extending through the end cap 106 is a conduit 110 having an inlet end 112 extending outwardly from the cap 106 providing a shoulder 114 for receiving an end of an air hose or conduit 116. A clamp 118 is conveniently used to secure the hose 116 to the inlet 112. An outlet end 120 of the conduit 110 extends vertically above the body 104 and provides means 122 creating a low pressure region adjacent the outlet end 120 in response to liquid moving through the conduit 78. The low pressure creating means 122 includes a central section 124 comprising an extension of the wall of the conduit 110 and a pair of wings 126, 128 extending laterally across the path of water movement through the conduit 78 as suggested by the arrows 130 in FIG. 6. An analysis of pressures around the outlet end 120 of the fitting 90 will reveal a high pressure area upstream of the wings 126, 128

and a low pressure area downstream thereof. Since the outlet end 120 of the conduit 110 opens downstream of the wings 126, 128, the conduit 110 is open to a low pressure area inside the conduit 78. Since the pressure in the wash chamber 16 is essentially atmospheric pressure, the area immediately downstream of the section 124 and the wings 126, 128 is below atmospheric pressure. Consequently, air may be drawn through the hose 116 provided that the valve 132 therein is open. The valve 132 is conveniently of the solenoid operative type controlled by the timer 36.

As will be apparent from FIG. 4, the plug has three functions: it provides the capability of draining residual water from the conduit 78; it provides a trap for small miscellaneous items such as marbles, pebbles, bobby pins and the like; and it provides the capability of introducing air into the pump inlet providing a soft or aerated wash. The provision of the aeration plug 90 accordingly allows the assembly of dishwashers having a soft wash capability or dishwashers not having a soft wash capability while using the same pump inlet conduit. Since the drain plug 90 is substantially less expensive than the pump inlet conduit 56 and is substantially more convenient to store because of the size difference, it will be apparent that significant economies can be effected in the assembly of dishwashers and in the inventory of parts therefor.

It will be apparent that the opening through the conduit should be downstream of the wings 126, 128 to provide a low pressure area exposed to the conduit outlet 120. It is desirable to assure that the wings 126, 128 are oriented properly in the conduit 78. To this end, the fitting 86 may provide a notch 134 for registry with a protuberance 136 provided by the end cap 106.

It should be noted that wings 126, 128 of means 122 may be preselectively sized to create therebehind a low pressure region of a magnitude which gives a predetermined pressure drop in the area of low liquid pressure immediately downstream of the aeration plug 90; consequently, it is possible to size wings 126, 128 to meet the specific requirements of the several dishwasher models in the assignees product line. Thus, applicants arrangement provides a straightforward, inexpensive, easily maintained, readily adaptable means for providing a soft wash feature in any number of dishwashers for use when washing fine china, crystal, and the like. Applicant accomplishes his objective without having to change the washing liquid flow rate within the dishwasher, the air flow rate into the washing liquid stream or the position of the air inlet in the conduit from the sump to the pump.

Having thus described the invention, what is claimed 1. A dishwasher comprising a tub and a movable door providing together a wash chamber;

a rack and means mounting the rack for movement into and at least partially out of the wash chamber; means for spraying aerated washing liquid toward the rack including a spray mechanism in the wash chamber,

a pump having an outlet in communication with the spray mechanism and an inlet,

a conduit providing communication between the wash chamber and the pump inlet and including a closed side wall having a single opening therethrough for alternatively receiving an imperforate plug or an aeration plug;

an aeration plug in the opening including an air passage therethrough; and

means for selectively delivering air to the passage.

2. The dishwasher of claim 1 wherein the aeration plug comprises means for creating a low pressure area in the conduit exposed to the air passage outlet, the creating means being insertable through the side wall opening.

3. The dishwasher of claim 2 wherein the creating means comprises a liquid deflector upstream of the air passage outlet and the aeration plug includes means exterior of the opening for orienting the deflector upstream of the air passage outlet.

4. The dishwasher of claim 2 wherein the opening is downwardly directed, the conduit comprises a fitting extending around the opening providing a passage thereinto, and the aeration plug includes a body having a vertical peripheral side wall received in the fitting passage and substantially larger than the air passage, an open top and a closed bottom providing a trap for items moving through the conduit.

5. The dishwasher of claim 4 wherein the conduit includes a generally vertical section in communication with the wash chamber and a generally horizontal section in communication with the pump inlet, the downwardly directed opening being positioned in the horizontal section at a low elevation therein.

6. A dishwasher comprising a tub and a movable door providing together a wash chamber;

a rack and means mounting the rack for movement into and at least partially out of the wash chamber; and

means for spraying aerated washing liquid toward the rack including a spray mechanism in the wash chamber,

a pump having an outlet in communication with the spray mechanism and an inlet,

a conduit providing communication between the wash chamber and the pump inlet including a downwardly extending opening for alternatively receiving an imperforate plug or an aeration plug,

an aeration plug sealed relative to the opening and providing therethrough an air passage, and

means for selectively delivering air to the passage.

7. The dishwasher of claim 6 wherein the aeration plug comprises means for creating a low pressure area in the conduit adjacent the air passage outlet, the creating means being insertable through the side wall openmg.

8. The dishwasher of claim 6 wherein the creating means comprises a liquid deflector upstream of the air passage outlet and the aeration plug includes means exterior of the opening for orienting the deflector upstream of the air passage outlet.

9. The dishwasher of claim 6 wherein the opening is downwardly directed, the conduit comprises a fitting extending around the opening providing a passage thereinto, and the aeration plug includes a body having a vertical peripheral side wall received in the fitting passage and substantially larger than the air passage, an open top and a closed bottom providing a trap for items moving through the conduit. 

1. A dishwasher comprising a tub and a movable door providing together a wash chamber; a rack and means mounting the rack for movement into and at least partially out of the wash chamber; means for spraying aerated washing liquid toward the rack including a spray mechanism in the wash chamber, a pump having an outlet in communication with the spray mechanism and an inlet, a conduit providing communication between the wash chamber and the pump inlet and including a closed side wall having a single opening therethrough for alternatively receiving an imperforate plug or an aeration plug; an aeration plug in the opening including an air passage therethrough; and means for selectively delivering air to the passage.
 2. The dishwasher of claim 1 wherein the aeration plug comprises means for creating a low pressure area in the conduit exposed to the air passage outlet, the creating means being insertable through the side wall opening.
 3. The dishwasher of claim 2 wherein the creating means comprises a liquid deflector upstream of the air passage outlet and the aeration plug includes means exterior of the opening for orienting the deflector upstream of the air passage outlet.
 4. The dishwasher of claim 2 wherein the opening is downwardly directed, the conduit comprises a fitting extending around the opening providing a passage thereinto, and the aeration plug includes a body having a vertical peripheral side wall received in the fitting passage and substantially larger than the air passage, an open top and a closed bottom providing a trap for items moving through the conduit.
 5. The dishwasher of claim 4 wherein the conduit includes a generally vertical section in communication with the wash chamber and a generally horizontal section in communication with the pump inlet, the downwardly directed opening being positioned in the horizontal section at a low elevation therein.
 6. A dishwasher comprising a tub and a movable door providing together a wash chamber; a rack and means mounting the rack for movement into and at least partially out of the wash cHamber; and means for spraying aerated washing liquid toward the rack including a spray mechanism in the wash chamber, a pump having an outlet in communication with the spray mechanism and an inlet, a conduit providing communication between the wash chamber and the pump inlet including a downwardly extending opening for alternatively receiving an imperforate plug or an aeration plug, an aeration plug sealed relative to the opening and providing therethrough an air passage, and means for selectively delivering air to the passage.
 7. The dishwasher of claim 6 wherein the aeration plug comprises means for creating a low pressure area in the conduit adjacent the air passage outlet, the creating means being insertable through the side wall opening.
 8. The dishwasher of claim 6 wherein the creating means comprises a liquid deflector upstream of the air passage outlet and the aeration plug includes means exterior of the opening for orienting the deflector upstream of the air passage outlet.
 9. The dishwasher of claim 6 wherein the opening is downwardly directed, the conduit comprises a fitting extending around the opening providing a passage thereinto, and the aeration plug includes a body having a vertical peripheral side wall received in the fitting passage and substantially larger than the air passage, an open top and a closed bottom providing a trap for items moving through the conduit. 